This invention relates to a composite tube for a gun barrel and more particularly to a composite tube including carbon fibers and a resin matrix material, and a method for constructing such a tube.
Composite gun barrels are desirable because they permit the construction of lightweight firearms. A composite barrel such as one constructed from a tube made of carbon fiber and epoxy resin materials, however, typically lacks sufficient stiffness to maintain its integrity for accurate reproducible firing. Even when the composite barrel includes an inner tubular liner, a firearm having such a composite barrel tends to be less accurate than a firearm having a conventional barrel.
Gladstone et al., U.S. Pat. No. 4,646,615, disclose a gun barrel produced by first filling the longitudinally-extending channels in a mandrel with rovings of an epoxy resin-impregnated carbon fiber and then wrapping the resin-impregnated carbon fiber around the mandrel in both hoop-wound and helically-wound layers.
Friar et al., U.S. Pat. No. 5,054,224, disclose an apparatus and method for producing a disposable composite gun tube by winding a resin-impregnated carbon filament fiber around a mandrel in alternate helical and hoop wraps.
May, U.S. Pat. No. 4,685,236, discloses a gun barrel constructed with an inner tubular liner and an outer jacket of a helically wound carbon fiber-reinforced metal matrix material.
Stein, U.S. Pat. No. 4,729,806, discloses a method for the manufacture of a composite tube by first applying pressure to a metal liner blank in a pressure chamber to impart an even thickness to all parts of the liner wall, and thereafter wrapping the exterior of the liner with a resin-impregnated fiber material.
Oskarsson et al., U.S. Pat. No. 5,191,165, disclose a method of producing a rifled, non-metallic barrel of composite material by first coating a mandrel with a continuous fluffy fiber mat, drenching the mat with a resin, and then surrounding the resin-drenched fiber mat with a plurality of resin-impregnated fiber layers disposed peripherally about the mandrel.
None of these references discloses, however, a composite tube for a gun barrel with sufficient bore stiffness for accurate reproducible firing.
Thus, a need exists for an improved composite tube for a gun barrel that overcomes the problems of prior composite tubes.
According to one aspect of the present invention, such a need is satisfied by a tube for a gun barrel defining a longitudinal bore axis, including a plurality of elongate carbon fibers and a resin material surrounding the longitudinal bore axis. The elongate carbon fibers are aligned parallel with the longitudinal bore axis and are under compression along the longitudinal bore axis.
According to another aspect of the present invention, such a tube for a gun barrel is made by wrapping a tubular metal liner with a resin matrix material containing a plurality of elongate carbon fibers, and aligning the carbon fibers parallel with the longitudinal axis of the liner. The resin matrix material is cured, and the elongate carbon fibers are placed under compression along the longitudinal axis of the liner. Compressing the carbon fibers along the longitudinal axis of the liner produces a tube of surprising stiffness. Thus, it is possible to produce a gun barrel of reduced weight with maximum projectile control and stabilization but minimal deformation, which is essential for maximum accuracy.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.